package com.example.alldemo.interceptor;

import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


@Component
public class InterceptorConfig implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("拦截器：方法执行前");
        //String num = request.getParameter("num");
        if ( StringUtils.isEmpty(request.getParameter("num"))) {
            System.out.println("拦截num为空");
            return false;
        }
//        else if (num == null || num == "") {
//            System.out.println("拦截num为空");
//            return false;
//        }
        System.out.println("拦截num不为空");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}
